Passive Vibration Control and Tunable Damping of MEMS Resonators via Electrical Autoparametric Resonance

Suppression of spurious vibrations and accurate control of mechanical damping is critical in MEMS devices to ensure optimal performance, sensitivity and reliability. Conventional control schemes such as feedback-based mechanical vibration absorbers or viscous dampers are either complex to implement at the micro scale or result in a higher sensor noise floor due to thermomechanical processes. In this paper, we present a tunable electrical autoparametric vibration control scheme that is applied to a capacitive MEMS resonator. In the proposed method, energy is transferred from the primary mechanical resonating element to a secondary electrical resonator via parametric mode coupling, thereby enabling dramatic reduction in the amplitude of mechanical vibration without introducing significant linear damping. As the threshold for parametric coupling is determined by electrical resistance, the system can be tuned easily to adjust the magnitude, rate and bandwidth of vibration suppression in the mechanical structure. A 1D lumped parameter model is developed to numerically analyse the behavior of the autoparametric vibration control system followed by experiments performed using a micromachined resonator array to validate the proposed model. The proposed circuit-based scheme provides an easily integratable and tunable solution to control damping in MEMS sensors and actuators. [2021-0095]